Boiler systems have been used to regulate the temperature of commercial and residential facilities for a number of years. However, despite the fact that boiler systems have been around for many years, innovations continue to change the manner in which these systems operate.
Conventional boiler controllers are often configured to constrain a temperature of a medium (e.g., water) comprised within a boiler (or other type heating appliance) between a low limit (LL) and a high limit (HL). The high limit (HL) is employed to prevent the medium temperature from exceeding some predetermined level to avoid a situation where a medium having an undesirably high temperature reaches a recipient. The low limit (LL) is typically set by a technician or as a default value to maintain the medium at some minimum level.
The low limit (LL) is important in extending the life and improving the safety of boilers. For example, excessive cold boiler starts may cause the boiler block to crack due to the thermal shock of starting a cold boiler. Furthermore, cold boiler water causes condensation of combustion flue products, which can accelerate corrosion of vent systems and heat exchangers. If the corrosion causes a breach of the vent system, combustion products may enter the home and pose a health hazard to its occupants.